1. Field of the Invention
The present invention relates to a cyclobutanetetracarboxylate compound and a preparation method thereof.
2. Description of the Prior Art
Cyclobutanetetracarboxylic dianhydrides are important monomer materials for the preparation of an alignment film useful for flat panel displays. Japanese Laid-open Hei 2003-192685 discloses a process for producing cyclobutanetetracarboxylic dianhydride comprising irradiating maleic anhydride to synthesize the cyclobutanetetracarboxylic dianhydride. This process, however, suffers from the shortcomings of a low yield in the production of the butane structure.
To overcome the above shortcomings, the inventors of the subject application developed a new synthesis route comprising synthesizing a cyclobutanetetracarboxylate, hydrolyzing the cyclobutanetetracarboxylate, and dehydrating the hydrolyzed product to obtain the corresponding cyclobutanetetracarboxylic dianhydride. The new route according to the present invention achieves an improved yield of the desired compounds.